Conventionally, in a manufacturing process of a semiconductor device, a flat display, or the like, a single-substrate processing apparatus has been used to perform a cleaning process or an etching process on a substrate such as a semiconductor wafer or a liquid crystal substrate.
In such a single-substrate processing apparatus, a substrate transfer chamber elongated in a forward/backward direction is formed at a central portion of a rectangular box-shaped case, and a multiple number of substrate processing chambers are arranged at left and right sides of the substrate transfer chamber in the forward/backward direction.
In this substrate processing apparatus, substrates are loaded one by one into each processing chamber by using a substrate transfer device provided in the substrate transfer chamber, and after the substrates are processed one by one in each substrate processing chamber, the processed substrates are unloaded from each substrate processing chamber one by one by using the substrate transfer device (see, for example, Patent Document 1).    Patent Document 1: Japanese Patent Laid-open Publication No. 2008-34490
In the aforementioned conventional substrate processing apparatus, however, since the substrates are transferred one by one by the substrate transfer device, it takes a long time to complete the transfer of the substrates in the substrate processing apparatus.
Thus, in the substrate processing apparatus, it has been required to improve throughput of substrate processing by shortening the time required for the transfer of the substrates.
As a means to reduce the time required for the transfer of the substrates, it might be considered to increase a moving speed of the substrate transfer device. However, since the substrate transfer device should transfer the substrates while allowing the substrates to be stably held thereon, there has been a limit in increasing the moving speed of the substrate transfer device.